David,
Don't forget that Workbench is also a perfectly legitimate platform for working in Mathematica, and primarily displays in ASCII. Programming with these Unicode characters with the ungainly \[...] names is a serious pain, and makes for uniquely unreadable code.
Also, camel case is fine when just typing symbol names, but I am currently working on an application where I need to generate symbol names. Without some kind of delimiting character, some of the generated names may conflict or not be readable. I ended up using $ out of sheer necessity, as it is on e of the few ASCII non- alphanumeric characters available for naming.
Daniel